Scatterplot axes

Please, could someone help me figure out what seems to be a very simple
problem (and is still taking me hours...).
I want to draw a simple scatterplot but with 'equal' axes, i.e. I want both
axes to go from -3 to 3. Values for x lie between -2 and 0.5, values for y
between -2.2 and 3. I have tried 'usr' and 'eqscplot' and a few other
options, but it doesn't give me the desired result.
Many thanks!!!
Ellen